1. Field of the Invention
The present invention relates to an editing apparatus and an editing method for editing for example audio data recorded on a record medium.
2. Description of the Related Art
As a related art reference of a highly efficiently encoding method for an audio signal, for example, a transform encoding method is known. The transform encoding method is one example of a block-segmentation frequency band dividing method. In the transform encoding method, a time-base audio signal is segmented into blocks at intervals of a predetermined unit time period. The time-base signal of each block is converted into a frequency-base signal (namely, orthogonally transformed). Thus, the time-base signal is divided into a plurality of frequency bands. In each frequency band, blocks are encoded. As another related art reference, a sub band coding (SBC) method as an example of a non-block-segmentation frequency band dividing method is known. In the SBC method, a time-base audio signal is divided into a plurality of frequency bands and then encoded without segmenting the signal into blocks at intervals of a predetermined unit time period.
As another related art reference, a highly efficiently encoding method that is a combination of the band division encoding method and the SBC method is also known. In this highly efficiently encoding method, a signal of each sub band is orthogonally transformed into a frequency-base signal corresponding to the transform encoding method. The transformed signal is encoded in each sub band.
As an example of a band dividing filter used for the above-described sub band coding method, for example a QMF (Quadrature Mirror Filter) is known. The QMF is described in for example R. E. Crochiere xe2x80x9cDigital coding of speech in sub bandsxe2x80x9d Bell Syst. Tech. J. Vol. 55. No. 8 (1976). An equal band width filter dividing method for a poly-phase quadrature filter and an apparatus thereof are described in ICASSP 83, BOSTON xe2x80x9cPolyphase Quadrature filtersxe2x80x94A new sub band coding techniquexe2x80x9d, Joseph H. Rothwiler.
As an example of the orthogonal transform method, an input audio signal is segmented into blocks at intervals of a predetermined unit time period (for each frame). Each block is transformed by for example a fast Fourier transforming (FFT) method, a discrete cosine transforming (DCT) method, or a modified DCT transforming (MDCT) method. As a result, a time-base signal is converted into a frequency-base signal. The MDCT is described in for example ICASSP 1987, xe2x80x9cSub band/Transform coding Using Filter Bank Designs Based on Time Domain Aliasing Cancellationxe2x80x9d, J. P. Princen and A. B. Bradley, Univ. of Surrey Royal Melbourne Inst. of Tech.
On the other hand, an encoding method that uses a frequency division width in consideration of the hearing characteristics of humans for quantizing each sub band frequency component is known. In other words, so-called critical bands of which their band widths are proportional to their frequencies have been widely used. With the critical bands, an audio signal may be divided into a plurality of sub bands (for example, 25 sub bands). According to such a sub band coding method, when data of each sub band is encoded, a predetermined number of bits is allocated for each sub band. Alternatively, an adaptive number of bits is allocated for each sub band. For example, when MDCT coefficient data generated by the MDCT process is encoded with the above-described bit allocating method, an adaptive number of bits is allocated to the MDCT coefficient data of each block of each sub band. With the allocated bits, each block is encoded.
An example of a related art reference of such a bit allocating method and an apparatus corresponding thereto is described as xe2x80x9ca method for allocating bits corresponding to the strength of a signal of each sub bandxe2x80x9d in IEEE Transactions of Acoustics, Speech, and Signal Processing, vol. ASSP-25, NO. 4, August (1977). As another related art reference, xe2x80x9ca method for fixedly allocating bits corresponding to a signal to noise ratio for each sub band using a masking of the sense of hearingxe2x80x9d is described in ICASP, 1980, xe2x80x9cThe critical band coderxe2x80x94digital encoding of the perceptual requirements of the auditory systemxe2x80x9d, M. A. Kransner MIT.
When each block is encoded for each sub band, each block is normalized and quantized for each sub band. Thus, each block is effectively encoded. This process is referred to as block floating process. When MDCT coefficient data generated by the MDCT process is encoded, the maximum value of the absolute values of the MDCT coefficients is obtained for each sub band. Corresponding to the maximum value, the MDCT coefficient data is normalized and then quantized. Thus, the MDCT coefficient data can be more effectively encoded. The normalizing process can be performed as follows. From a plurality of numbered values, a value used for the normalizing process is selected for each block using a predetermined calculating process. The number assigned to the selected value is used as normalization information. The plurality of values are numbered so that they increment by 2 dB of an audio level.
The above-described highly effectively encoded signal is decoded as follows. With reference to the bit allocation information, the normalization information, and so forth for each sub band, MDCT coefficient data is generated corresponding to a signal that has been highly efficiently encoded. Since a so-called inversely orthogonally transforming process is performed corresponding to the MDCT coefficient data, time-base data is generated. When the highly efficiently encoding process is performed, if the frequency band is divided into sub bands by a band dividing filter, the time-base data is combined using a sub band combining filter.
When numbered normalization information is changed by an adding process, a subtracting process, or the like, a reproduction level adjusting function, a filtering function, and so forth can be accomplished for a time-base signal of which a highly efficiently encoded data has been decoded. According to this method, since the reproduction level can be adjusted by a calculating process such as an adding process or a subtracting process, the structure of the apparatus becomes simple. In addition, since a decoding process, an encoding process, and so forth are not excessively required, the reproduction level can be adjusted without a deterioration of the signal quality. In addition, in this method, even if a highly efficiently encoded signal is changed, since the time period of the decoded signal does not vary, when numbered normalization information is changed, part of the signal generated by the decoding process can be changed. As a result of a partial change of such a signal, for example, a fade-in process and a fade-out process can be performed for a music program recorded on a disc. In this case, in the fade-in process, the fade-out process, and so forth, parameters of transition time, transition shape, transition start position, and transition end position can be designated. Thus, the fade shape can be more accurately formed.
As a record medium on which a signal that has been highly efficiently encoded is recorded, an MD (mini disc) that is a magneto-optical disc is known. In addition, an MD system that records and/or reproduces data such as audio data using an MD as a record medium is known. By adding a structure that performs a process for reflecting a changed result of numbered normalization information to recorded data to such an MD system, an editing function can be accomplished.
In the record format of an MD, besides a main data record area such as audio data, a management information area for recording information that represents a recorded area and a non-recorded area for data is formed. The management information area is referred to as U-TOC (User-Table Of Contents). When data is recorded on an MD, a non-recorded area is detected with reference to U-TOC. When data is reproduced from an MD, a area in which desired data has been recorded is detected with reference to U-TOC.
In U-TOC, the area in which recorded data such as audio data has been written is managed for each music program as a unit referred to as track. In other words, the start address, the end address, and so forth of each track are recorded. When the-contents of U-TOC are updated, recorded data can be edited. As examples of such an editing process, a dividing process for dividing one track into a plurality of tracks, a combining process for combining a plurality of tracks to one track, a moving process for changing track numbers of tracks in the reproducing order of a normal reproducing operation rather than a shuffle-reproducing operation, and an erasing process for erasing an unnecessary track can be easily and quickly performed.
However, when an editing process such as a fade-in process, a fade-out process, or the like is performed by changing normalization information of highly efficiently encoded information, the user may want to change the remaining data. For example, when the end address of a track of which the fade-out process has been performed does not match the last transition positon of the fade-out process, if the region between the end address and the last position is treated as a new track, it may be detected as an unnecessary region. In such an editing process, by updating the contents of U-TOC, the region can be divided or erased.
In particular, after performing an editing process such as a fade-out process, he or she may want to perform a dividing process, an erasing process, or the like. Such an operation can be accomplished in such a manner that while checking the last transition position of the fade-out process with a rehearsal reproducing operation (namely, a trial reproducing operation), the user designates a dividing position, an erasing position, or the like. However, such an operation is very troublesome for the user. In addition, when the user designates an edit position for only an audio output as a rehearsal reproduction output, it is difficult to accurately designate the last transition position of the fade-out.
In addition, there is a case that an editing process for substituting a data region for the fade-out process with zero data or almost zero data is desired. Such an editing process cannot be accomplished by only a process for updating the contents of U-TOC. Such a problem mainly takes place in the fade-out process. However, it may take place in the fade-in process or the like.
Therefore, an object of the present invention is to provide an editing apparatus and an editing method that allow a desired second editing process in association with a first editing process for changing normalization information or the like to be easily and accurately performed.
A first aspect of the present invention is an editing apparatus for editing a highly efficient encoded digital signal recorded on a record medium having a program area for recording programs and a management area for recording management information, each of the programs being composed of a digital signal containing at least normalization information that has been highly efficiently encoded corresponding to normalization information, quantization coefficients, and quantization data calculated for each of a plurality of signal components divided in time-base direction and/or frequency-base direction, the management information being used to manage at least a record start position and a record end position of each of the programs recorded on the program area, comprising an operating means for designating an edit start position and an edit end position to vicinities of end portions of a predetermined program recorded in the program area of the record medium, a reproducing means for reproducing a digital signal between the edit start position and the edit end position corresponding to the vicinities of the end portions of the predetermined program recorded in the program area of the record medium, a changing means for changing normalization information contained in the digital signal reproduced by the reproducing means, a recording means for substituting the normalization information changed by the changing means with the normalization information contained in the digital signal reproduced by the reproducing means and re-recording the substituted normalization information to the record medium to the vicinities of the end portions of the predetermined program recorded in the program area of the record medium corresponding to the edit start position and the edit end position, and a management information editing means for editing the management information recorded in the management area of the record medium against the vicinities of the end portions of the predetermined program recorded in the program area of the record medium corresponding to the edit start position and the edit end position.
A second aspect of the present invention is an editing method for editing a highly efficient encoded digital signal recorded on a record medium having a program area for recording programs and a management area for recording management information, each of the programs being composed of a digital signal containing at least normalization information that has been highly efficiently encoded corresponding to normalization information, quantization coefficients, and quantization data calculated for each of a plurality of signal components divided in time-base direction and/or frequency-base direction, the management information being used to manage at least a record start position and a record end position of each of the programs recorded on the program area, comprising the steps of reproducing a digital signal between the edit start position and the edit end position corresponding to the vicinities of the end portions of the predetermined program recorded in the program area of the record medium, changing normalization information contained in the digital signal reproduced at the reproducing step, substituting the normalization information changed at the changing step with the normalization information contained in the digital signal reproduced at the reproducing step and re-recording the substituted normalization information to the record medium to the vicinities of the end portions of the predetermined program recorded in the program area of the record medium corresponding to the edit start position and the edit end position, and editing the management information recorded in the management area of the record medium against the vicinities of the end portions of the predetermined program recorded in the program area of the record medium corresponding to the edit start position and the edit end position.
A third aspect of the present invention is an editing apparatus for editing a highly efficient encoded digital signal recorded on a record medium having a program area for recording programs and a management area for recording management information, each of the programs being composed of a digital signal containing at least normalization information that has been highly efficiently encoded corresponding to normalization information, quantization coefficients, and quantization data calculated for each of a plurality of signal components divided in time-base direction and/or frequency-base direction, the management information being used to manage at least a record position of each of the programs recorded on the program area, comprising an operating means for selecting a program to be edited and an edit region, a reproducing means for reproducing a digital signal including at least normalization information corresponding to the edit region selected by the operating means and management information from a management area of the record medium, a first storing means for storing the management information for managing at least record positions of individual programs, the management information being reproduced from the management area of the record medium, a second storing means for storing a digital signal including at least normalization information reproduced by the reproducing means, a rewriting means for rewriting normalization information in a digital signal including at least normalization information stored in the second storing means, a controlling means for overwriting a digital signal including normalization information rewritten by the rewriting means to the record medium corresponding to management information stored in the first storing means, a comparing means for comparing the record position of a program to be edited, the record position being stored in the first storing means with an edit region selected by the operating means, and a selecting means for detecting a remaining area as an edited result corresponding to the compared result of the comparing means and for selecting a process type for the detected remaining area.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.